Electronic devices, such as smartphones, are increasingly supporting use cases, where for certain functionality, it is desirable for the device to be able to support a larger display size. For example, larger display sizes can be desirable for viewing visual content as part of a media player or a browser, as well as for supporting the visual presentation of information as part of an application or program that is being executed by the device. However, such a trend needs to be balanced with a general desire for the overall size of the device to stay the same and even decrease in one or both of dimension and weight.
In an attempt to support larger display sizes without increasing the overall size of the device, device manufacturers have increasingly dedicated a larger percentage of the exterior surface to a display, where the display in many instances has grown in one or more dimensions to a size that dominates a particular surface, such as the front surface of the device. In at least some of these instances, the display has been allowed to extend into areas that had previously been used to support user inputs, such as areas of the surface that have previously supported a keypad, such as a numeric keypad.
Larger displays often mean larger openings in the housing, which can reduce the amount of material that is available to support the structural integrity of the housing, and correspondingly the device. As such, manufacturers are increasingly relying upon materials in the formation of the device housings, such as metals, that have historically better maintained structural integrity with less overall material. This is true for devices having a full metal rear housing, as well as devices that incorporate perimeter metal housings. However, housings made from conductive materials, such as metal, can interfere with the transmission and reception of wireless signals into and out of the device. Further openings can be made in the housing proximate the location of the antennas, which support wireless communication signal transmission/reception, in order to create an area through which wireless signaling can propagate. Alternatively, the antennas can be formed into the housing materials with cuts and/or further openings which isolate the antenna portions from the non-antenna portions of the housing. However, to the extent that cuts or further openings need to be made in the housing, the further openings and/or cuts can further affect the structural integrity. The further openings and/or cuts can also affect the aesthetics of the device.
Furthermore, to the extent that one or multiple antenna(s) are formed in the housing, the size and shape of the housing of the device can affect the size, shape and spacing of the corresponding antenna(s). This in turn can affect the ability of multiple antennas associated with a conductive housing to operate together at the same or similar frequencies including instances in which there is a desire for multiple antennas to support antenna diversity in support of wireless radio frequency communications.
The present innovators have recognized that by controlling the geometry of the antenna elements formed in a housing, as well as the interaction of the antenna elements, including the higher current portions of the antenna elements, with a conductive substrate, one can affect the polarity of the signals that are more optimally transmitted or received by the structure. In turn the relative differences in polarity of the more optimally transmitted and received signals by the various antenna structures can help to reduce the correlation between relatively closely spaced antennas in support of antenna diversity in a hand-held sized device.